Fracture in lamellar TiAl simulated with the cohesive model

Werwer, M.; Kabir, Rizviul; Cornec, A.; Schwalbe, K.‐H.

doi:10.1016/j.engfracmech.2006.09.022

Cited by 16 publications

(8 citation statements)

References 27 publications

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“…As it is seen in Fig. 6 the experimentally obtained value is reproduced quite well for the reasonable content of α 2 phase (again, not clearly reported in [42]).…”

Section: Elastic Propertiessupporting

confidence: 65%

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Micromechanical Model of Polycrystalline Materials with Lamellar Substructure

Kowalczyk-Gajewska¹

2011

Archives of Metallurgy and Materials

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Micromechanical model of polycrystalline materials with lamellar substructure is presented. The lamellar microstructure of grains is accounted for using the well-established framework developed for layered composites. Within the approach different scale transition rules between the level of lamellar grain and the polycrystalline sample can be employed. The model capabilities are tested using the example of α2 + γ-TiAl intermetallic. Elastic properties and the initial yield surface for the lamellar grain (PST crystal) and for the untextured polycrystal are estimated. Elastic and plastic anisotropy degree is analyzed.

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“…As it is seen in Fig. 6 the experimentally obtained value is reproduced quite well for the reasonable content of α 2 phase (again, not clearly reported in [42]).…”

Section: Elastic Propertiessupporting

confidence: 65%

“…The most significant difference is obtained for intermediate directions. In [42] the Young modulus E = 175 GPa for the polycrystalline TiAl of lamellar microstructure has been measured. The extrusion texture of a tested sample indicates the case for which the direction n is close to be perpendicular to the tension direction.…”

Section: Elastic Propertiesmentioning

confidence: 99%

Micromechanical Model of Polycrystalline Materials with Lamellar Substructure

Kowalczyk-Gajewska¹

2011

Archives of Metallurgy and Materials

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“…However, more atomistic insights are still necessary to understand the thermomechanical deformation behavior of a single lamellar interface in γ-TiAl at elevated service temperatures. Our understanding of the combined microscopic effects and mechanisms occurring in plasticity and fracture of TiAl still remains limited (Appel et al, 2016), even though some small-scale testing has been conducted revealing the failure mechanisms in the microstructure (Werwer et al, 2007;Barbi et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

“…These phenomenological models initially developed to handle discontinuities due to crack propagation and fracture (Hillerborg et al, 1976;Li and Chandra, 2003;Scheider, 2018) can be embedded in finite element models by the so-called interface elements to also describe the material separation behavior at both macroscale and micro-scale interfaces (Scheider, 2009a;Simonovski and Cizelj, 2015;Scheider, 2018). For lamellar γ-TiAl, micromechanical lamellae separation has been studied in Werwer and Cornec (2000), Werwer et al (2007), and Wei et al (2009). Cohesive zone models rely on a traction-separation law (TS law).…”

Section: Introductionmentioning

confidence: 99%

Quantifying the High-Temperature Separation Behavior of Lamellar Interfaces in γ-Titanium Aluminide Under Tensile Loading by Molecular Dynamics

2021

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γ-titanium aluminide (TiAl) alloys with fully lamellar microstructure possess excellent properties for high-temperature applications. Such fully lamellar microstructure has interfaces at different length scales. The separation behavior of the lamellae at these interfaces is crucial for the mechanical properties of the whole material. Unfortunately, quantifying it by experiments is difficult. Therefore, we use molecular dynamics (MD) simulations to this end. Specifically, we study the high-temperature separation behavior under tensile loading of the four different kinds of lamellar interfaces appearing in TiAl, namely, the γ/α2, γ/γPT, γ/γTT, and γ/γRB interfaces. In our simulations, we use two different atomistic interface models, a defect-free (Type-1) model and a model with preexisting voids (Type-2). Clearly, the latter is more physical but studying the former also helps to understand the role of defects. Our simulation results show that among the four interfaces studied, the γ/α2 interface possesses the highest yield strength, followed by the γ/γPT, γ/γTT, and γ/γRB interfaces. For Type-1 models, our simulations reveal failure at the interface for all γ/γ interfaces but not for the γ/α2 interface. By contrast, for Type-2 models, we observe for all the four interfaces failure at the interface. Our atomistic simulations provide important data to define the parameters of traction–separation laws and cohesive zone models, which can be used in the framework of continuum mechanical modeling of TiAl. Temperature-dependent model parameters were identified, and the complete traction–separation behavior was established, in which interface elasticity, interface plasticity, and interface damage could be distinguished. By carefully eliminating the contribution of bulk deformation from the interface behavior, we were able to quantify the contribution of interface plasticity and interface damage, which can also be related to the dislocation evolution and void nucleation in the atomistic simulations.

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“…Titanium aluminide (TiAl) crystal structures, reproduced from[94], with permission from Elsevier, 2007.…”

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confidence: 99%

Spark Plasma Sintering of Titanium Aluminides: A Progress Review on Processing, Structure-Property Relations, Alloy Development and Challenges

Mogale

Matizamhuka

2020

Metals

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Titanium aluminides (TiAl) have the potential of substituting nickel-based superalloys (NBSAs) in the aerospace industries owing to their lightweight, good mechanical and oxidation properties. Functional simplicity, control of sintering parameters, exceptional sintering speeds, high reproducibility, consistency and safety are the main benefits of spark plasma sintering (SPS) over conventional methods. Though TiAl exhibit excellent high temperature properties, SPS has been employed to improve on the poor ductility at room temperature. Powder metallurgical processing techniques used to promote the formation of refined, homogeneous and contaminant-free structures, favouring improvements in ductility and other properties are discussed. This article further reviews published work on phase constituents, microstructures, alloy developments and mechanical properties of TiAl alloys produced by SPS. Finally, an overview of challenges in as far as the implementation of TiAl in industries of interest are highlighted.

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Fracture in lamellar TiAl simulated with the cohesive model

Cited by 16 publications

References 27 publications

Micromechanical Model of Polycrystalline Materials with Lamellar Substructure

Micromechanical Model of Polycrystalline Materials with Lamellar Substructure

Quantifying the High-Temperature Separation Behavior of Lamellar Interfaces in γ-Titanium Aluminide Under Tensile Loading by Molecular Dynamics

Spark Plasma Sintering of Titanium Aluminides: A Progress Review on Processing, Structure-Property Relations, Alloy Development and Challenges

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